A number of communication devices enable multiple computing devices to communicate between different types of networks. Examples of such devices include gateways, routers, switches, bridges, hubs, firewalls, and the like. The computing devices may use a communication device to communicate between different types of LANs, such as between an Ethernet network and a Token Ring network. Alternatively, or additionally, the computing devices may use a communication device to communicate between an internal LAN and a WAN, such as between an Ethernet LAN and the Internet. Many communication devices can also auto-sense an operating speed on each of multiple ports, so that the device automatically communicates at 10 megabits per second (MBPS), 100 MBPS, or 1000 MBPS based upon the speed of the network to which a port is connected. Similarly, many communication devices can auto-negotiate between half and full duplex on a port. However, both the speed auto-sense and the duplex auto-sense assume predefined protocol capabilities for the communication line coupled to the port. For example, speed auto-sense involves determining the highest speed of a node that a port is connected to and adjusting the port transmission rate accordingly. Thus, the speed auto-sense is actually a predefined request/response interaction whereby each end of the communication line recognizes a request for maximum speed capability and provides a response according to the Ethernet protocol to the other end of the line.
In a similar fashion, some modems can auto-sense which protocol to use on a WAN connection over a telephone line, such as a V.90 protocol or a K56 Flex protocol. However, modems typically use a designated port or interface for connecting to a universal serial bus (USB) port or an RS-232 serial port on a single computing device. Alternatively, a modem can be connected to a gateway, which enables multiple computing devices to share the WAN connection made through the modem. Sharing a high speed WAN connection through a digital subscriber line (xDSL) interface or through a cable modem is increasingly popular for home networks and small business networks. Unfortunately, configuring a gateway or other communication device to share a WAN connection between multiple computing devices is often a confusing and frustrating process, especially for home users who do not have the required networking knowledge and skills to configure networks.
One source of confusion and error in configuring a communication device, such as a gateway, is determining which port on the device should be used for the WAN connection, and which are used for the LAN connection(s). Some communication devices allow a user to manually configure any port to be the WAN port. However, such manual configuration usually involves a series of software and/or hardware selections that most home users find daunting. Thus, most communication devices that are marketed to home users have a single port that is dedicated to, and labeled as the WAN port. Other ports are typically labeled as LAN ports. Nevertheless, many home users do not understand the difference between a WAN and a LAN, or otherwise can not distinguish between the WAN and LAN ports. As a result, sometimes a LAN line is incorrectly connected to the WAN port and/or the WAN line is incorrectly connected to a LAN port. This simple error may go unnoticed, causing the user to waste time and become frustrated trying to determine why the home network does not work as expected. To eliminate these problems, it would be desirable for a communication port to automatically configure itself for the type of line connected to the port—either WAN or LAN.
In a manner similar to the auto-sensing techniques discussed above, plug-and-play technology enables a computer to automatically detect the presence of a peripheral device that has been newly connected to the computer and then to automatically configure the computer to communicate with the peripheral device. Upon detecting a new peripheral device, a predetermined enumeration process is carried out by the computer according to a standard communication protocol, such as USB. The enumeration process enables the computer to determine the capabilities of the peripheral device and load appropriate software for driving and interfacing with the peripheral device. However, as with auto-sensing, plug-and-play technology requires a predetermined enumeration process that is expected and understood by both the computer and the peripheral device. A universal plug-and-play (UPnP) standard has been proposed by an industry initiative called the Universal Plug-and-Play Forum. UPnP defines a communication standard whereby a device can dynamically join a network, obtain an internet protocol (IP) address, convey its capabilities, and learn about the presence and capabilities of other devices. All devices on the network must listen to a standard multicast address for discovery messages from a newly joined device, and respond if a match is determined with search criteria of the discovery message. However, this again requires a predefined discovery process that is expected and understood by both the newly added device and other devices on the network. A formal predefined discovery process could be applied to ports of a communication device, but it would be preferable if each port could distinguish between an internal (e.g., LAN) connection and an external (e.g., WAN) connection with less processing overhead than is required by a formal protocol that requires predetermined discovery processing on both ends of the connection.
Other attempts have been made to enable a port to handle multiple types of communications. For example, some existing switches can map any port as the WAN port. However, the mapping is predetermined. The mapping is not defined in response to auto-detecting a WAN connection made to a port. As another example, Mapletree Networks, Inc. provides a UNIPORTE® architecture wherein each port can process various types of communication, such as modem, fax, integrated services digital network (ISDN), voice over IP (VoIP), fax over IP (FoIP), and voice over digital subscriber line (VoDSL). According to Mapletree Networks, Inc. product literature, each port can be dynamically reconfigured by sensing the type of incoming call, identifying an available port, assigning the call to the available port, and loading a software module into a digital signal processor (DSP) to enable the port to process the type of call sensed. Although flexible, this architecture requires a DSP for each port, and substantial processing overhead is required for configuring each port. This architecture also requires a reduced instruction set computer (RISC) processor to perform protocol processing functions, such as voice/data packet framing, error correction, compression, and jitter buffer management. It would clearly be preferable to provide ports that can distinguish between a LAN connection and a WAN connection with fewer components and less processing than is needed in the prior art approach.